Such a data processing system used for controlling brakes of the vehicle is discussed in DE 19 634 567 A1.
This typical system includes a pedal unit, which establishes reference variables for partial braking forces for the wheels of the front axle and rear axle, and wheel pair units, which receive the reference variables and output activation variables for electric actuators of the brakes. The bus system is divided into a first communication system, via which the first wheel pair unit powered by a first vehicle electrical system communicates with the pedal unit, and a second communication system, via which the second wheel pair unit powered by a second vehicle electrical system communicates with the pedal unit. The division of the bus system into two separate communication systems allows continuation of the communication with the remaining wheel pair unit if one wheel pair unit or the vehicle electrical system powering it fails, so that the brakes controlled by this wheel pair unit remain capable of acting. However, a line interruption on one of the communication systems results in the failure of the communication between units connected to this communication system in any case, so that the danger of partial failure of the brake system is not negligible.
A ring bus system which allows undisturbed continuation of the communication of units with one another in case of interruption of a single connection between two units is discussed in DE 10 223 007 A1. If one considers the possibility of powering units of this known system by various vehicle electrical systems, it may be seen that a failure of a vehicle electrical system which powers multiple units will very probably result in a complete failure of the communication on the ring bus.